The frequency shift demodulator circuit composed of active filter

Published:2011/6/16 21:09:00 Author:qqtang | Keyword: frequency shift demodulator, active filter | From:SeekIC

Replacing LC modulation circuit by the active filter, we can avoid using large and expensive inductance coils in frequency shift key control demodulator, it is not only small in size, but also improves the function of the demodulator. This circuit is used to demodulate the 100 byte frequency shift key control signal, whose symbol frequency is 2225Hz, open frequency is 2025Hz. The filter A allows the open frequency to pass, and the filter B allows the symbol frequency to pass, therefore , when the symbol frequency in on the input terminal, the transistor is saturated and the output is short.



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